1. Download all Bangla font from https://github.com/bulbul5391/all_bangla_font

git clone ...repo...url...

2. Now go to /usr/local/share/fonts directory and create a folder. example "bangla"

sudo mkdir bangla
sudo chmod -R 777 bangla

3. After that copy all bangla fonts not folder and past in sample folder
4. fc-cache -f -v
5. Then close browser and open browser